def test_rotation_matrix_2d(self):
		self.assertTrue(np.equal(cde.rotation_matrix_2d(0.0), 
				np.array([[1, 0], [0, 1]])).all)
		self.assertTrue(np.equal(cde.rotation_matrix_2d(np.pi), 
				np.array([[-1, 0], [0, -1]])).all)
		r2o2 = 1.0 / np.sqrt(2.0)
		self.assertTrue( np.equal(cde.rotation_matrix_2d(-np.pi/4), 
				np.array([[r2o2, r2o2], [-r2o2, r2o2]])).all)
Exemplo n.º 2
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 def test_rotation_matrix_2d(self):
     self.assertTrue(
         np.equal(cde.rotation_matrix_2d(0.0), np.array([[1, 0], [0,
                                                                  1]])).all)
     self.assertTrue(
         np.equal(cde.rotation_matrix_2d(np.pi), np.array([[-1, 0],
                                                           [0, -1]])).all)
     r2o2 = 1.0 / np.sqrt(2.0)
     self.assertTrue(
         np.equal(cde.rotation_matrix_2d(-np.pi / 4),
                  np.array([[r2o2, r2o2], [-r2o2, r2o2]])).all)
	def test_orbital_step_time_simple(self):
		earth_vel = cde.earth_omega * cde.AU
		start_coords_1 = np.array([[cde.AU, 0.0], [0.0, earth_vel]]).T
		dt = cde.year / 360  #let's go forward one degree!
		one_deg = 2 * np.pi / 360.
		rot_coords = np.dot(cde.rotation_matrix_2d(one_deg), start_coords_1)
		final_coords = cde.orbital_step_time_simple(start_coords_1, dt)
		diff_coords = (rot_coords - final_coords) / rot_coords
		diff_coords_max = np.sqrt(
				max(np.dot(diff_coords[:,0], diff_coords[:,0]),
				np.dot(diff_coords[:,1], diff_coords[:,1])))
#Check to see if it's off by not more than a linear amount
		self.assertTrue(diff_coords_max < 1.0 / 360.0)
Exemplo n.º 4
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 def test_orbital_step_time_simple(self):
     earth_vel = cde.earth_omega * cde.AU
     start_coords_1 = np.array([[cde.AU, 0.0], [0.0, earth_vel]]).T
     dt = cde.year / 360  #let's go forward one degree!
     one_deg = 2 * np.pi / 360.
     rot_coords = np.dot(cde.rotation_matrix_2d(one_deg), start_coords_1)
     final_coords = cde.orbital_step_time_simple(start_coords_1, dt)
     diff_coords = (rot_coords - final_coords) / rot_coords
     diff_coords_max = np.sqrt(
         max(np.dot(diff_coords[:, 0], diff_coords[:, 0]),
             np.dot(diff_coords[:, 1], diff_coords[:, 1])))
     #Check to see if it's off by not more than a linear amount
     self.assertTrue(diff_coords_max < 1.0 / 360.0)
	def test_rk4_stepper(self):
		earth_vel = cde.earth_omega * cde.AU
		start_coords_1 = np.array([[cde.AU, 0.0], [0.0, earth_vel]]).T
		dt = cde.year / 360  #let's go forward one degree!
		one_deg = 2 * np.pi / 360.
		rot_coords_1 = np.dot(cde.rotation_matrix_2d(one_deg), start_coords_1)
		int_coords = cde.rk4_stepper(start_coords_1, .5 * dt)
		final_coords = cde.rk4_stepper(int_coords, .5 * dt)
		final_coords_2 = cde.rk4_stepper(start_coords_1, dt)
		log_diff_coords = (rot_coords_1 - final_coords_2) / rot_coords_1
		pos_err = np.sqrt(np.dot(log_diff_coords[:,0], log_diff_coords[:,0]))
		vel_err = np.sqrt(np.dot(log_diff_coords[:,1], log_diff_coords[:,1]))
		max_err = max(pos_err, vel_err)
#Good to within a part in a billion
		self.assertTrue(max_err < 1.0 * 10 ** -9)
Exemplo n.º 6
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 def test_rk4_stepper(self):
     earth_vel = cde.earth_omega * cde.AU
     start_coords_1 = np.array([[cde.AU, 0.0], [0.0, earth_vel]]).T
     dt = cde.year / 360  #let's go forward one degree!
     one_deg = 2 * np.pi / 360.
     rot_coords_1 = np.dot(cde.rotation_matrix_2d(one_deg), start_coords_1)
     int_coords = cde.rk4_stepper(start_coords_1, .5 * dt)
     final_coords = cde.rk4_stepper(int_coords, .5 * dt)
     final_coords_2 = cde.rk4_stepper(start_coords_1, dt)
     log_diff_coords = (rot_coords_1 - final_coords_2) / rot_coords_1
     pos_err = np.sqrt(np.dot(log_diff_coords[:, 0], log_diff_coords[:, 0]))
     vel_err = np.sqrt(np.dot(log_diff_coords[:, 1], log_diff_coords[:, 1]))
     max_err = max(pos_err, vel_err)
     #Good to within a part in a billion
     self.assertTrue(max_err < 1.0 * 10**-9)